Generally, magnetic memory disks in a disk memory device are arranged as a stack of disks and serve for storing data items on memory tracks which run concentrically to one another and to the axis of rotation of the stack of disks. The tracks are each scanned by an electromagnetic transducer head for carrying out a write or read process. The transducer head is held on the head arm, and the latter can be positioned on the individual magnetic memory tracks by the head arm carrier coupled with a drive by having the head arm either swung parallel to the magnetic memory disk or moved out in a radial direction. For this the transducer head is suspended with a small spacing above or below the respective magnetic memory disk. Two transducer heads are provided for each magnetic memory disk, which heads are moved over or under the magnetic memory disk on their head arm so that the disk is usable as double sided. If a number of magnetic memory disks are provided, then a corresponding number of transducer heads are held one over another in the manner of a stack on the head arm carrier common to them.
Due to various environmental influences, especially by contaminations or unintentional contact between the transducer heads and the magnetic memory disks, the surfaces of the latter can be damaged over long periods of use. Because of this it is advisable to inspect the magnetic memory disks so that they can be replaced when their magnetic coating medium is too greatly impaired. Previously for this purpose the magnetic memory disks had to be removed from the magnetic disk memory and subjected to optical inspection, which in some cases might cause further impairment or damages. In particular, centering defects can occur in this way, avoiding which would require a relatively large expenditure of work in reinstalling the magnetic memory disks.